ENH Pass microxs settings to MicroXSReader

[drewejohnson]

Is your feature request related to a problem? Please describe.
Spin out from #339 to focus on providing relevant settings to the microxs reader at construction

Describe the solution you'd like
Communicate at construction if various items should be collected or not, e.g.,

r = MicroXSReader(
    fp,
    getFlux=False,
    getXS=True,
    getFY=False,
)

Describe alternatives you've considered
Using the global settings object which #339 intends to deprecate

Additional context
Deprecation timeline #339 (comment)